internal class CustomDotDensityStyle : DotDensityStyle
{
    protected override void DrawSampleCore(GeoCanvas canvas, DrawingRectangleF drawingExtent)
    {
        base.DrawSampleCore(canvas, drawingExtent);
        PointShape upperLeftPoint = ExtentHelper.ToWorldCoordinate(canvas.CurrentWorldExtent, drawingExtent.CenterX - drawingExtent.Width / 2, drawingExtent.CenterY - drawingExtent.Height / 2, canvas.Width, canvas.Height);
        PointShape lowerRightPoint = ExtentHelper.ToWorldCoordinate(canvas.CurrentWorldExtent, drawingExtent.CenterX + drawingExtent.Width / 2, drawingExtent.CenterY + drawingExtent.Height / 2, canvas.Width, canvas.Height);
        RectangleShape rectangle = new RectangleShape(upperLeftPoint, lowerRightPoint);
        rectangle.ScaleDown(10);

        // Here draw the points on Legend Image
        Random random = new Random(DateTime.Now.Millisecond);
        Collection<BaseShape> drawingPoints = new Collection<BaseShape>();
        for (int i = 0; i < DrawingPointsNumber; i++)
        {
            double x = rectangle.LowerLeftPoint.X + random.NextDouble() * (rectangle.Width);
            double y = rectangle.LowerLeftPoint.Y + random.NextDouble() * (rectangle.Height);
            drawingPoints.Add(new PointShape(x, y));
        }
        TextStyle textStyle = new TextStyle(DrawingPointsNumber.ToString(), new GeoFont("Arial", 20, DrawingFontStyles.Bold), new GeoSolidBrush(GeoColor.FromArgb(180, GeoColor.FromHtml("#d3d3d3"))));
        textStyle.DrawSample(canvas, drawingExtent);
        CustomPointStyle.Draw(drawingPoints, canvas, new Collection<SimpleCandidate>(), new Collection<SimpleCandidate>());
    }
}